Re: [netmod] comments on draft-ietf-netmod-yang-instance-file-format-04

[Balázs Lengyel <[e-mail]>]

-----Original Message-----
From: Martin Bjorklund <[e-mail]> 
Sent: 2019. november 18., hétfő 0:53
To: Balázs Lengyel <[e-mail]>
Cc: [e-mail]; [e-mail]
Subject: Re: [netmod] comments on draft-ietf-netmod-yang-instance-file-format-04

> > On Thu, Oct 10, 2019 at 5:06 AM Martin Bjorklund <[e-mail] <mailto:[e-mail]> > wrote:
> > 
> > 
> >   o  leaf-list module
> > 
> >     The type of this leaf-list is a string with:
> > 
> >       pattern '.+@\d{4}-\d{2}-\d{2}\.yang';
> > 
> >     I think the revision needs to be optional, and the suffix ".yang"
> >     dropped, since it doesn't add any value:
> > 
> >       pattern '.+(@\d{4}-\d{2}-\d{2})?';
> > 
> >    (same for inline-spec).
> > 
> >  
> > 
> > IMO the filespec SHOULD follow the pattern in
> > https://tools.ietf.org/html/rfc7950#section-5.2
> > 
> > BALAZS: It does follow the pattern except that I made the revision date mandatory. It is needed to properly understand the instance data.
> > 
> >  
> > 
> > Except a new file extension SHOULD be used.
> > 
> > Suggest: .yif == YANG Instance File
> > 
> >  
> > 
> > Obviously it would be a horrible idea to use .yang since that 
> > extension
> > 
> > is already used to identify a YANG schema file.
> > 
> > BALAZS: The leaf-list lists not the instance data files but the content defining YANG modules, so IMO “.yang” is an appropriate extension. It is really a YANG schema file we are listing.
> 
> No, you are not listing a file name, you are listing the name and, optionally, the revision of a YANG *module*.  It can internally be stored as a .yang file a .yin file, or as a blob in a database.
> 
> Hence, we should not have the ".yang" suffix here.
> BALAZS2:
> OK, I will add the '.yin' possibility.

IMO this is even worse.  Which suffix should I use?  What difference does it make?

> I would like to keep the file extension because 
> [e-mail] looks more familiar

I think it is a bad idea to use something that looks familiar but change the meaning of it.  It is *not* a filename, it is a pair modulename + optional revision; an identifier for the module.

, will be easier to understand, than just
> ietf-yang-types@2019-12-07
> IMHO in practice systems might very well use it for file lookup.

But if I use this for file lookup, and I use YIN, and I try to use an instance file that lists the modules as ".yang", this won't work.


Perhaps solve this by changing the leaf-list into:

  container inline-modules {
    list module {
      key name;
      leaf name { ... }
      leaf revision { ... }
    }
  }

/martin

BALAZS3: People explicitly asked for a short, simple solution, so reusing the well-known module-file-naming format seemed logical,  and nobody misunderstood it till now.
I would really like to avoid creating a list with 2 separate leaf's: longer, more complex. It goes against the express wishes of other group members.
If you prefer we can drop the file extension. IMHO it will look strange.


I think a file loader can have the intelligence to look for a yin if yang is not found or vice-versa.
/Balazs